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Electrical and mechanical anharmonicities from NIR‐VCD spectra of compounds exhibiting axial and planar chirality: The cases of ( S )‐2,3‐pentadiene and methyl‐ d 3 ( R )‐ and ( S )‐[2.2]paracyclophane‐4‐carboxylate
Author(s) -
Abbate Sergio,
Longhi Giovanna,
Gangemi Fabrizio,
Gangemi Roberto,
Superchi Stefano,
Caporusso Anna Maria,
Ruzziconi Renzo
Publication year - 2011
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.21013
Subject(s) - chemistry , chirality (physics) , anharmonicity , vibrational circular dichroism , overtone , planar chirality , molecular physics , density functional theory , spectral line , molecule , computational chemistry , axial chirality , infrared spectroscopy , molecular vibration , circular dichroism , crystallography , physics , quantum mechanics , organic chemistry , chiral symmetry breaking , enantioselective synthesis , nambu–jona lasinio model , catalysis , quark
The IR and Near infrared (NIR) vibrational circular dichroism (VCD) spectra of molecules endowed with noncentral chirality have been investigated. Data for fundamental, first, and second overtone regions of ( S )‐2,3‐pentadiene, exhibiting axial chirality, and methyl‐ d 3 ( R )‐ and ( S )‐[2.2]paracyclophane‐4‐carboxylate, exhibiting planar chirality have been measured and analyzed. The analysis of NIR and IR VCD spectra was based on the local‐mode model and the use of density functional theory (DFT), providing mechanical and electrical anharmonic terms for all CH‐bonds. The comparison of experimental and calculated spectra is satisfactory and allows one to monitor fine details in the asymmetric charge distribution in the molecules: these details consist in the harmonic frequencies, in the principal anharmonicity constants, in both the atomic polar and axial tensors and in their first and second derivatives with respect to the CH‐stretching coordinates. Chirality, 2011. © 2011 Wiley© Liss, Inc.